Interference tube for phonographs and telephones



M. E. WOLVEKAMP. INTERFERENCE TUBE FOR PHONOGRAPHS AND TELEPHGNES. APPUCATIUN FILED MAR. I6, 1920.

1,429,993, Patented Sept. 26, I922.

w'l-mzssfs Ma 31 W0 e rgggron Patented Sept. 26, 1922.

UNITED STATES MARI ELIZE WOL'V'EKAMP, OE OAKLAN D, CALIFORNIA.

INTERFERENCE TUBE FOR PHONQGRAIHS AND TELEPHONES.

Application filed March 16, 1920. SerialNo. 866,872

and it consists substantially in the construotion and arrangement herein described and claimed.

The foremost object of the invention is to provide a tube to be fitted between the tone arm and reproducer of a phonograph, for the purpose of intercepting or interfering with certain undesirable high tones which ordinarily make their presence known by a bi h and often strong whistle.

ther objects and advantages will appear in the following specification, reference being had to the accompanying drawing, in which Figure 1 is a plan view illustrating the embodiment of the interference tubes in the tone arm of a phonograph,

Figure 2 is a horizontal section illustrating a slight modification wherein the large U tube is made extensible,

Figure 3 is a horizontal section illustrating how the branches on which the extensible U tube is fitted may be entirely closed by a stopper when desired,

Fi ure 4 is a detail cross section illustratingjhat the extensible U tube is made round,

iigure 5 is a detail cross section illustrating how it may be made oval in shape instead of round, and Figure 6 is a detail view of a modification wherein the interference tube is used in connection with a telephone receiver.

In carrying out my invention, I provide the main tube 1. which is of uniform diameter and is bent so as to provide a branch to which the sound reproducer R is fitted as at 2, and a branch to which the tone arm T is attached as at 3.

In the form of the invention in Figure 1, there are two interference tubes, the first consisting of the elbow 4 and the other of a U tube 5. Both of these are integral with the main tube 1 and are of precisely the same diameter. There either mayor may not be a division wall between the elbow 4 and the crook of the main tube 1, this being as desired, although Figures 2 and 3 show such division wall.

In Figure 2 the U tube 5"is made extensible, short branches 6 being suitablyfastened to the main tube 1 in place of the integral U tube 5 in Figure 1, on which branches the U tube5 slides in and out, as is readily to be understood from Figure 2.

There maybe occasions when it becomes desirable to discard the extensible U tube 5" altogether. In such event, a stopper consisting of aplate (with plugs8 is fitted in place as in Figure 3: This stopper-includes a ring 9 by which it is readily manipulated. The

inner surfaces of the plugs 8 come exactly flush'with the interior wall of the main tube 1, when the stopper is inserted as in Figure 3.

Instead of making the U tube 5 round, as in Figure 4, it may be made oval as in Figure 5, there being instances when this latter form is preferable in use to the former.

The advantages and operation, may be briefly pointed out to advantage. The underlying principle of this invention is to interfere with or eliminate certain undesirable sound waves, by allowing those waves to simultaneously traverse paths of different length so that they are totally eliminated so far as the resultant production is concerned.

The method employed. namely, the provision of the elbow 4 and U tube 5, enables the removal of the disagreeable tones, and mostly those that are high or metallic and which produce the disagreeable whistle that very often accompanies voices which are otherwise beautifully reproduced on the well known makes of records. This high whistling sound is estimated to be constituted of sound vibrations of approximately 2800 vibrations per second or of a wave length equal to about twice 2% inches.

It therefore necessarily follows that by providing a by-pass of approximately 2% inches longer. by the presence of the larger U-tube 5 in Figure 1, the false tones represented by the above whistling sound, are entirely eliminated and makes records producing them agreeable to hear. It may be found in actual practice that only the elbow 4 is required to produce the desired result, then again in other cases, it may be found necessary to employ the U-tube 5. Or in still other cases, it may be found necessary to have the U-tube 5* extensible. Theusepf these interference tubes makes the voice shorter. clearer and more distinct and very expressed, may be applied with, suecessito the receiver of a telephone, by connecting a horn of the receiver \vitha U-tube ofequal diameter forming a by-passfor the sound.

It is desired to point out that the use of the interference tube is not confined=to application to the tone arm of a phonograph because the interference tube ,may be employed in connection with atelephone re-- ceiver, as for example'R in Figure 6. hen

used in this connection, the interference tube 1 PBXfOllDSFPIIBClSGlY the same-function that it performs when used ma tone arm, namely,

eliminates the -hi h rorfalse and. objectionable tones that .o ten are. sopiercing to the ear of the listener. It is shown assimply; inserted in the outlet of the receiver on-front of the diaphragm d, the U-tube 5 being of, recisely the same arrangement as that in *i re 1.

of the tone interference tubes as herein -dee ile the construction and arrangement" scribed and claimed, is that of a generally preferred form, obviously modifications and changes can be made Without departing from the spirit ofthe invention or the scope of the claims.

1. In combination with the reproducer and. with the tone arm of a phonograph, a relatively narrow main sound conduit including by-pass means the ends ofwhich are close together and communicate with said sound conduit, permitting two lame and substantially-equal volumes. of sound to simultaneously' traverserpaths of distinctly difierent lengths which are not varied by. the movement at the Phono mph, eliminating by interfelience a high or also tone.

2. In combination with the reproducer and with the tone arm of a phonograph, a relatively marrow main sound conduit provided with twoil-ateral openingsclose together and communicating with both endsof a U.-tube, permittingtwo large and substantially equal volumes of sound to-simultaneously tnaverse paths of distinctly different lengths which are not varied :by lthezmovement of the phonograph, eliminating or--false tone.

MARI ELIZE WOLVEKAML by interference a high 

